Celestia Forums

I'm very excited about the upcoming Phoebe flyby by Cassini on Friday. The Cassini imaging team just release this set of images, taken from distances ranging from 4.1 to 2.5 million kilometers:

http://saturn.jpl.nasa.gov/cgibin/gs2.c ... type=image

Cassini will fly within 2000km of Phoebe, and details as small as 15 meters should be visible in the images. What does it mean for Celestia? For one, we'll need a texture that's about 48k x 24k to capture all the details from the Cassini images. Of course, only a small portion of the surface will be imaged at such high resolution--a Phoebe virtual texture perhaps?

It's fortunate that Phoebe is not in synchronous rotation; with a rotation period of only 9.3 hours, all of the surface should be illuminated at some point during the encounter. According to JPL, the entire surface should be mapped in color at between 0.3 and 2.1 km/pixel. The only gaps in a surface map of Phoebe will be at 'poles' invisible to Cassini . . .

--Chris

It's already time for this encounter?! My, how time flies. This will be exceedingly cool though

BTW, I notice that Cassini appears to be oriented incorrectly in Celestia - the dish should be pointing towards the Earth, shouldn't it? I don't think it's using a low gain antenna now that's oriented differently is it? Or is it?

Evil Dr Ganymede wrote:BTW, I notice that Cassini appears to be oriented incorrectly in Celestia - the dish should be pointing towards the Earth, shouldn't it?

Should be, but there's no way to maintain that orientation in Celestia at present.

Grant

As I understand it this will be Cassini's only enouncter with Phoebe will it not? Due to Phoebe retrograde, distant and inclined orbit, I should think this particular fly-by is very important science wise. Not only is it the start of the actual mission but its the first time we've ever seen this small moon from within 2 million Km.

Also this gives us something to chew on between June 11 and July 1 when Cassini reaches SOI.

Evil Dr Ganymede wrote:BTW, I notice that Cassini appears to be oriented incorrectly in Celestia - the dish should be pointing towards the Earth, shouldn't it? I don't think it's using a low gain antenna now that's oriented differently is it? Or is it?

AFAIK Cassini doesn't always keep the dish pointed Earthwards.
That's why pictures of the encounter will be sent back to Earth no earlier than Saturday.

I was watching the encounter with Celestia, and funnily enough the bright patches on the current Phoebe map at this stage of it seem to correspond very closely with the bright patches in the image. Must be coincidence since I don't think the Phoebe map is based on anything known so far, but I thought it was kinda cool

Evil Dr Ganymede wrote:BTW, I notice that Cassini appears to be oriented incorrectly in Celestia - the dish should be pointing towards the Earth, shouldn't it? I don't think it's using a low gain antenna now that's oriented differently is it? Or is it?

In the orbiter forum someone asked the same and here is what i remember from the asnwer: The dish its not only a dish, but also some kind of shelter: when cassini croses the rings, just before the SOI burn, the antenae will protect the craft from small rocks and ice...

Erk. I hope the "small rocks and ice" don't damage the dish then... if this turns into Galileo and we lose the HGA here again, I will in all likelihood want to kill someone.

The Cassini encounter with Phoebe will happen pretty quickly.

More images are coming in.

http://ciclops.lpl.arizona.edu/view.php ... e39cddbf22

Are there any good 3d modellers out there?

The Cassini team just release another couple images of Phoebe, the best one taken from a distance of 658,000km:



--Chris

Evil Dr Ganymede wrote:Erk. I hope the "small rocks and ice" don't damage the dish then... if this turns into Galileo and we lose the HGA here again, I will in all likelihood want to kill someone.

Dont worry... it wont happen...
BTW: if in the dish appear some holes, it wont affect the dish...

A which time the flyby is??

ElPelado wrote:A which time the flyby is??

When the dish will point to Earth again?We are in the middle of Saturday and there isn?t any Cassini near picture of Phoebe.JPL said that the pictures will be release today.Maybe only at the middle of the night?

+ + + Update! + + +

Here are the latest (released) pictures from Phoebe. And these aren't even the highest resolution pictures... (the best ones are about 10 times the resolution!). I'm sure they'll be releasing more over the next few days...



http://photojournal.jpl.nasa.gov/catalog/PIA06066

...And i can't wait to see them either, the Cassini mission is going to be absolutely fantastic!

Phoebe is one battered place isn't it...

Cassini's mission is to explore Saturn's moons, right? What's its primary objective, Europa?

Will this mission in any way help us to determine anything about the Europan oceans?

--Starman

Actually, Europa orbits Jupiter. Cassini is at Saturn, which is the mission's primary target. however, as far as moons go, the one that will garner the most interest will be Titan.

Here's the mission's home page: http://saturn.jpl.nasa.gov/index.cfm

The next big goal is the orbital insertion on July 1. here's looking forward to a long and prosperous mission!

...John...

New pictures!!! (they're too big to post here, but they're awesomely high resolution!).

http://ciclops.lpl.arizona.edu/view.php?id=197 The Face of Phoebe

http://ciclops.lpl.arizona.edu/view.php?id=196 Phoebe's Surprise

http://ciclops.lpl.arizona.edu/view.php?id=193 Crater closeup on Phoebe

Why is it called Phoebe's Surprise?

because nobody ever expected a body formed in space, with no weather, to have layers of materials of different types.